464 Professor Sir Henry E. Eoseoe [April 16, 



into moulds of wood or iron, and allowed to cool and solidify. The 

 lumps are at length taken from the moulds, broken up small, and dried 

 in a drying-room, and subsequently in a drying apparatus heated 

 with steam, until quite desiccated. 



Step V. — The sodium sulphonate salts are now converted into 

 their corresponding sulphonic chlorides. This is effected as follows: — 

 The dried sulphonates are thoroughly mixed with phosphorus tri- 

 chloride, itself as dry as possible. The mixture is then placed in 

 lead-lined iron vessels, and a current of chlorine is passed over the 

 mixture till the reaction is ended. The temperature generated by 

 the reaction must be properly regulated by cooling the apparatus 

 with water. The phosphorus oxychloride resulting from the decom- 

 position is driven off, collected, and utilised for developing chlorine 

 from bleaching powder for the chlorinating process, phosphate of 

 lime being precipitated, which can be used in manures. For this 

 purpose the oxychloride is treated with water, and the mixture, now 

 containing hydrochloric and phosphoric acids, is brought into contact 

 with the chloride of lime. 



The reaction by which the ortho- and para-toluene sulphonic 

 chlorides are produced is indicated by the following equation : — 



^^^^SOaNa + (^^^^ + 2^^) = ^«^^ {sO.Cl + ^^^^3 + NaCl 



Toluene sulphonic chlorides 



The two sulphonic chlorides remaining in the apparatus are 

 allowed to cool slowly, when the solid one (the para compound) is 

 deposited in large crystals, so that the liquid one can bo easily 

 removed by the aid of a centrifugal machine. The crystalline residue 

 is freed from all the liquid sulphonic chloride by washing with cold 

 water. Only the liquid orthotoluene sulphonic chloride is capable of 

 yielding saccharine, and the liquid product above separated is cooled 

 with ice to crystallise out the last traces of the crystalline compound. 

 The solid parasulphonic chloride obtained as by-product, is decom- 

 posed into toluene, hydrochloric, and sulphurous acids by mixing it 

 with carbon, moistening the mixture, and subjecting it under pressure 

 to the action of superheated steam. The total change proceeds in two 

 stages : — 



1- ^^H^oh + I^^« = C.H,{^^3^jj + HCl. 



2. 2 (CeH,|^'o,bH) + C = 2 (C„H,.CH3) + CO^ + SO^. 



The toluene is then used again in Stej^ I., and the hydrochloric and 

 sulphurous acids in Step VII. 



Step YI. — The liquid orthotoluene sulphonic chloride is now 

 converted into the orthotoluene sulphonic amide by treating the former 

 with solid ammonium carbonate in the required proj^ortious, and sub- 

 jecting the resulting thick pulpy mixture to the action of steam. 



